Lactic acid bacteria polysaccharide

J. Ceming, Exocellular polysaccharides produced by lactic acid bacteria, FEMS Microbiol. Rev., 1 (1990) 113-130. 

Wine lactic acid bacteria can degrade polysaccharides and O. oeni has been shown to have an extracellular (3 (l->3) glucanase activity (Guilloux-Benatier et al. 2000). 

The lactic acid bacteria may cause polysaccharides to be released in a wine (Dols-Lafalgue et al. 2007). These compounds can increase the sensation of volume or body of wines, and can also be polymerized with the grape or wood tannins, reducing sensations of roughness or astringency, and producing more complex flavours. 

The interaction between aroma compounds and other wine micro-organisms (e.g. lactic acid bacteria) or with metabolites produced during malolactic fermentation has been studied to a limited extent. Interactions between polysaccharides produced by the most common wine lactic bacteria (Oenoccocus oeni) during malolactic fermentation have been shown to be responsible for the reduced volatility of some aroma compounds in wines (Boido et al. 2002). The possibility of direct interactions between the surface of the bacteria cells and aroma compounds should also be considered since this type of interaction has been found for other food lactic bacteria (Ly et al. 2008). 

Lactic acid bacteria are used to produce fermented milk products, and the exopolysaccharides produced by the bacteria influence the texture of the resulting products. More importantly, these exopolysaccharides are thought to have several health benefits. There is evidence they lower cholesterol, modulate the immune system, help prevent colon cancer, and fight ulcers [342,343]. There is thus interest in establishing stmcture-function relationships for these stmctures, as well as in metabolic engineering of lactic acid bacteria to produce capsular polysaccharides with the desired properties [342,343]. 

With few exceptions, enzymatic processes in carbohydrates cause degradation. Enzymes are used in the form of pure or semipure preparations or together with their producers, i.e., microorganisms. Currently, semisynthetic enzymes are also in use. Alcoholic fermentation is the most common method of utilization of monosaccharides, sucrose, and some polysaccharides, e.g., starch. Lactic acid fermentation is another important enzymatic process. Lactic acid bacteria metabolize mono- and disaccharides into lactic acid. This acid has a chiral center thus either D(-), L(+), or racemic products can be formed. In the human organism, only the L(+) enantiomer is metabolized, whereas the D(-) enantiomer is concentrated in blood and excreted with urine. Among lactic acid bacteria, only Streptococcus shows specificity in the formation of particular enantiomers, and only the L(+) enantiomer is produced. 

Korakli, M., Ganzle, M.G., and Vogel, R.F. 2002. Metabolism by bifidobacteria and lactic acid bacteria of polysaccharides from wheat and rye, and exopolysaccharides produced by Lactobacillus sanfranciscensis. J. Appl. Microbiol. 92, 958-965. 

Most polysaccharides used today are of plant origin. However, also bacteria produce polysaccharides. Especially extracellular polysaccharides (eps s) produced by lactic acid bacteria may find application in foods. Lactic acid bacteria are food-grade organisms and the eps s produced offer a wide variety of structures. The presence of eps is considered to contribute greatly to texture and structure of fermented milk products. An exopolysaccharide produced by Lactococcus lactis ssp. cremoris B40 was chosen as a subject of study. The eps was a gift from the Dutch Institute of Dairy Research (NIZO), Ede, the Netherlands. The eps had no gelling properties, could not be precipitated in plates by ethanol or cetylpyridinium chloride and did not show interaction with Congo red. 

Lactic acid bacteria synthesise a range of different polysaccharides, defined by their location in the cell. Some are located intracellularly and are used as energy or carbon sources others are cell wall components and some are located outside the cell wall. The latter are called extracellular polysaccharides (EPs) and are either associated with the cell wall as a slime capsule, or secreted into the environment. Many lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermo-philus and Lactococcus lactis subsp. cremoris produce EPs. 

Cerning, J., Bouillane, C., Landon, M. and Desmazeaud, M.J. (1990) Comparison of exocellular polysaccharide production by thermophilic lactic acid bacteria. Sciences des aliments 10(2), 443-451. 

The synthesis of exocellular polysaccharides by lactic acid bacteria is a very widespread character. L. mesenteroides and Streptococcus mutans produce glucose homopolymers such as dextran and glucan fructose homopolymers (levans) and heteropolymers are also synthesized. Dextran of L. mesenteroides is the best known, as much for its different structures and its biosynthesis as for its various applications. 

In the literatnre, increased viscosity in ciders and beers is attribnted to different lactic acid bacteria species, notably P. damnosus mAL. brevis—which are also fonnd in wine (Williamson, 1959 Beech and Carr, 1977). Luthi (1957) established that the symbiosis between lactic acid bacteria producing polysaccharides and acetic bacteria accelerates the increase in viscosity of the medium. 

In addition to the influence of yeasts and other lactic acid bacteria, fungi and acetic bacteria present on infected grapes also affect wine lactic acid bacteria. The media precultivated by the above have varying effects on lactic acid bacteria multiplication with respect to the control media (San Romao, 1985 Lonvaud-Funel et al., 1987). Organic acids and polysaccharides accumulate in the medium and either impede or activate bacterial growth, but in practice they have little effect. Even if the grapes are tainted, these metabolites remain in insufficient concentrations to affect lactic acid bacteria. 

Ng, R and Keich, U. (2008) GIMSAN a Gibbs motif finder with significance analysis. Bioirtfomuttics 24, 2256-2257. Notararigo, S., Ndcher-Vazquez, M., Ibarburu, I., et al. (2013) Comparative analysis of production and purification of homo- and hetero-polysaccharides produced by lactic acid bacteria. Carbohydr Polym 93, 57-64. 

Nagaoka, M., Hashimoto, S., Watanabe, T., et al. (1994) Anti-ulcer effects of lactic acid bacteria and their cell wall polysaccharides. Biol Pharm Bull 17, 1012-1017. 

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